Pressure control



May 1,1928.

G. A. BROOKE, JR

PRESSURE CONTROL m QBRQ um Filed March 1924 Patented May 1, 1928.

GEORGE A BROOKE, JR, GERMANTQWN, PENNSYLVANIA.

PRESSURE CONTROL.

Application filed March My invention relates tov improvements in pressure control. The object is to provide im roved means for maintaining automatical y the required pressure of an expansible medium.

The invention comprises means for ut lizing changes in the pressure of the expanslble medium for operating a control for a motor, which in turn operates a damper or other controlling device to restore the medium to normal or predetermined pressure, so that, as the pressure of the medium tends to rise or fall, the automatic control operates to restore said pressure to normal and at the same time the exact movement of the motor which is determined by the direction and amount of pressure change, is utilized to stop the motor.

Referring to the drawings, which illus- 20 trate merely by way of example suitable means for effecting my invention 2- Fig. 1 is a sectional elevation of such means with diagram of electric circuits.

Fig. 2 is a diagrammatic plan view.

Fig. 3 is a detail in part section and part elevation.

Similar numerals refer to similar parts throughout the several views.

Assuming for example that the expansible to medium, the pressure or which is to be controlled, is the steam in a steam boiler or generator, and that a damper in the stack is utilized for regulating the fire which generates the steam, we conduct the steam through pipe 5 to an enclosed space 6 beneath the movable diaphragm 7, with the result that the diaphragm 7 rises and "falls in accordance with the pressure in 6. A. lever bar 8 is supported at the points 9 and 10 at or near one end, and is provided with the weight 11 connected at the other end, as at 12. The fulcrum 13 comprises a bar or trunnion formation having a knife edge 10 for engagement with a contact piece 14, of hardened metal, secured to the ends of the stationary lugs 15 which flank the end of bar 8. The other point of support is the knife edge formation 9, supported on the movable diaphragm 7, and engaging the contact piece 16 secured to the underside of bar 8.

The hand operated threaded rods 50 and 51 form adjustable abutments or stops for limiting the movement of the lever bar 8.

A bar 17 is pivotally secured to bar 8, as at 18. To this bar 17 is pivotally connected the link 19 provided toward its lower end is, 1924. Serial No. 700,128.

With slot 19' 20 connected to the bar through which projects a stud or lever 21 supported at one end, as at-22. The other end of bar or lever 21 carries two \vided with the contacts blades or plates pro- 23 and 24 which are adapted for alternate engagement with the contact points 25 and 26 respectively.

The contacts 25 and 26 may be called a minus and 6 minus, while contacts 23 and 24 represent plus, in their circuits.

The function of the control of the motor contacts 23,25 and 24,

26 is to control circuits operating magnetic contactors to close the motor, as indicated Fig. 1. ing of the motor when the neutral position.

f the arm 21 moves is as follows: line circuits operating the diagrammatically in This makes available dynamic brakthe arm 21 assumes up, the relay circuit wire 1, resistance R,

plus, contacts 23, 25, so enoid coil B, wire 72 to wire 4 to line minus.

This operates the pivoted spring or gravity controlled solenoid actuated switch 64.

en switch 64 is actuated, the armature circuit is as follows:

me plus, wire 1 to wire 70 to switch 64 to wire 63 armature right to left to wire 62,

switch 61'to contact minus.

Since the field circuit from line plus, to line run when the armature f arm 21 moves actuated and the versed.

The motor 27 is show with the last gear 29 30 is provided with a cured to the hub as at 71 to wire 4 to line is continually closed minus, the motor will is connected as above. down, the solenoid A is armature current is ren in Fig. 2 connected a four reduction gear. The hub 28 of which is mounted on shaft band or cable 31 se 32. This cable 31 is connected, through the adjustable turnbuckle 33 and the cable the bell crank lever 36, at 37. The other arm 36 is connected by the link 39 34, to one arm of pivotally mounted as 38 of this bell-crank to the bar 17,

as at 40, to the other side of the pivot support 18. The link 39 is spring 41.

Any desired gear of driven gears may be p tionship with a control,

also connected to the the train of motor ut in operative relasuch for example as a stack damper 42 as shown merely diagrammatically in Fig. 3. The damper 42 may be connected for example by means of lever 43,

to connecting rod 44, cr

ank arm 45, shaft 46,

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sprocket 47, chain 48 and sprocket 49 mounted on shaft 30, or the shaft of any other of the gears, as required.

In operation.

By the proper adjustment of the turnbuckl 33, when the pressure in 6 is at the desired point and the motor is in the required position, with respect to the damperor other device which it is designed to operate, the tension of cables 31 and 34 acting through bellcrank 36 and link 39, against sprmg 41, serves to bring bar 21 in such position that the contact points 23 and 24 will be in neutral position, that is, out of engagement with contacts 25 and 26. Upon increase of steam pressure in space 6, the diaphragm 7 is lifted causing a lifting of the left hand end of bar 8, which actuation is communicated through link 17 to cause the movement of bar 21 so that 23 is brought into contact with 25 the circuits as indicated on page 3, thereby causing the motor to operate for example, to close the damper 42, and check the draft, at the same time the very slight movement of drum 28, due to the four gear reductions referred to, pulls the bell-crank 36 in the clockwise direction against the pull of spring 41. This causes the elevation of the right hand end of bar 17 and the depression of the left hand end, and consequentl the depression of link 19 which ermits t e bar 21 to fall by ravity suificient y to separate contacts 23 rom contact 25. Whereupon the motor stops. Similarly upon occurrence of decrease of ressure in 6, the diaphragm 7 descends an through the connecting elements already described contacts 24 and 26 engage, causlng the motor to be moved in the opposite direction, moving bell-crank in counter-clockwise direction and, correspondingly, through the mechanism described, bar 21 is lifted sufiiciently to separate 24 and 26 and thus cause the motor to stop. In this way the operation may be re eated as often as required in either direction, depending upon change of pressure in 6 either upwardly or downwardly, to correct the same.

The action of the bar ,21 may be used to operate a motor reversibly by means of other and difierent circuits and electrical devices common to the art, the disclosure being merely by way of example.

The diaphragm 7 is preferably made of flexible and slightly elastic material and of such character that its resistance increases relatively to its distortion, due to change of pressure in 6. From this factor it follows that an increment change in pressure of fluid medium causes like incremental movement of a suitable actuator.

The movement of the motor is alwa s exactly roportional to the movement of ar 8, there ore the movement of the motor is always exactly proportional to the pressure change.

It will be understood that the purpose of spring 41 is to maintain constant tension of the cable 31, and theslot 19' is provided in link 19 to permit idle movement of the link in one direction only. Connecting holes are provided in bar 17 and bell crank 36 for preliminary adjustment, but the final adjustment is secured by the turnbuckle 33.

What I claim is In a ressure control, the combination of means orming a pressure chamber, a diaphragm associated therewith, a motor, a controlling device operated thereby, two motor circuits having stationary terminal contacts and a control for said circuits comprising a movable member provided with terminal contacts for cooperation with either of the stationary contacts, and means for communicating a magnified movement of the diaphragm to the movable contact member, operating to secure the actuation of the motor in direction corres onding to direction of pressure change an during an uninterrupted period corresponding to the amount of pressure change.

GEORGE A. BROOKE, JR. 

